Abridged ion trap-time of flight mass spectrometer
First Claim
Patent Images
1. An abridged trap-TOF mass analyzer comprising:
- an abridged linear ion trap witha plurality of rectilinear electrode structures each comprising a plurality of electrodes arranged along a line, each structure having a substantially planar face with a first dimension and a second dimension perpendicular to the first dimension and being constructed so that a voltage applied across the second dimension produces at the planar face an electrical potential whose amplitude is a linear function of position along the second dimension,a mechanism that positions the plurality of rectilinear electrode structures so that, for each electrode structure, the first dimension extends along the central axis and the planar faces of the electrode structures are parallel and positioned about the central axis,a source that applies an RF potential across the second dimension of each of the electrode structures to produce a multipole field to focus analyte ions toward the central axis, andone or more trapping electrode assemblies that produce axially confining fields before and after the plurality of electrode structures along the central axis;
a drift region; and
an ion detector.
1 Assignment
0 Petitions
Accused Products
Abstract
An improved trap-TOF mass spectrometer has a set of electrodes arranged to produce both a quadrupolar RF confining field and a substantially homogeneous dipole field. In operation, ions are first confined by the RF field and then, at a selected time, the RF confining field is discontinued and the dipole field is used to accelerate the ions so as to initiate a TOF MS analysis. The apparatus of the present invention may be used alone or in conjunction with other analyzers to produce mass spectra from analyte ions.
51 Citations
27 Claims
-
1. An abridged trap-TOF mass analyzer comprising:
-
an abridged linear ion trap with a plurality of rectilinear electrode structures each comprising a plurality of electrodes arranged along a line, each structure having a substantially planar face with a first dimension and a second dimension perpendicular to the first dimension and being constructed so that a voltage applied across the second dimension produces at the planar face an electrical potential whose amplitude is a linear function of position along the second dimension, a mechanism that positions the plurality of rectilinear electrode structures so that, for each electrode structure, the first dimension extends along the central axis and the planar faces of the electrode structures are parallel and positioned about the central axis, a source that applies an RF potential across the second dimension of each of the electrode structures to produce a multipole field to focus analyte ions toward the central axis, and one or more trapping electrode assemblies that produce axially confining fields before and after the plurality of electrode structures along the central axis; a drift region; and an ion detector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A method of mass analyzing ions comprising:
-
(a) providing an abridged trap-TOF mass analyzer comprising a first abridged linear ion trap with a plurality of rectilinear electrode structures each comprising a plurality of electrodes arranges along a line, each structure having a substantially planar face with a first dimension and a second dimension perpendicular to the first dimension and being constructed so that a voltage applied across the second dimension produces an electrical potential at the planar face whose amplitude is a linear function of position along the second dimension;
a mechanism that positions the plurality of rectilinear electrode structures so that, for each electrode structure, the first dimension extends along the central axis and the planar faces of the electrode structures are parallel and positioned about the central axis; and
one or more trapping electrode assemblies which can be used to produce axially confining fields before and after the plurality of electrode structures along the central axis, a drift region and an ion detector;(b) injecting analyte ions into the first abridged linear ion trap along the central axis; (c) applying an RF potential across the second dimension of each of the electrode structures so as to produce a multipole field to focus the analyte ions toward the central axis; (d) discontinuing the RF potential; (e) applying a DC potential to one of (i) between the plurality of electrode structures and (ii) across the second dimensions of the electrode structures so that a first substantially homogeneous dipole field is established to accelerate the analyte ions out of the first abridged linear ion trap and into the drift region; and (f) detecting the ions. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
-
-
27. A method of mass analyzing ions comprising:
-
providing an abridged trap-TOF mass analyzer comprising a first abridged linear ion trap with a plurality of rectilinear electrode structures, each structure having a substantially planar face with a first dimension and a second dimension perpendicular to the first dimension and being constructed so that a voltage applied across the second dimension produces an electrical potential at the planar face whose amplitude is a linear function of position along the second dimension;
a mechanism that positions the plurality of rectilinear electrode structures so that, for each electrode structure, the first dimension extends along the central axis and the planar faces of the electrode structures are parallel and positioned symmetrically about the central axis; and
one or more trapping electrode assemblies which can be used to produce axially confining fields before and after the plurality of electrode structures along the central axis, a drift region and an ion detector;receiving analyte ions into the first abridged linear ion trap along the central axis; applying an RF potential across the second dimension of each of the electrode structures so as to produce a multipole field to focus the analyte ions toward the central axis; discontinuing the RF potential; applying a DC potential to one of (i) between the plurality of electrode structures and (ii) across the second dimensions of the electrode structures so that a first substantially homogeneous dipole field is established to accelerate the analyte ions out of the first abridged linear ion trap and into the drift region; and detecting the ions, where the step of discontinuing comprises discontinuing the RF potential at a phase that is an integer multiple of π
in order to reduce the effect of ion micromotion on the TOF mass analysis.
-
Specification